Thames Water has appointed civil engineering contractor Barhale to carry out the £7.8m programme next to Gallions Reach shopping centre in Barking.
The existing 800mm twin Store Road rising main runs from the Store Road pumping station (just north of the Woolwich ferry terminal) to an outfall that discharges into the northern outfall sewer (NOS) near the Beckton sewage treatment works inlet.
Two sections of the twin mains will be rehabilitated. One section will require Barhale to replace the existing sewer with two lengths of 142-metre 800mm diameter high density polyethylene (HDPE) pipe, which will be installed through open cut excavation.
At the adjacent section, Barhale will repair a 220-metre length of each main using cured in place pipe (CIPP) relining. A temporary rider system will be deployed to isolate the works while allowing flows to be maintained.
After the pipeline work is completed, a prefabricated glass-reinforced plastic (GRP) discharge chamber will be installed.
Shane Gorman, Barhale’s water director for the southern region, explained that the chamber design needed to take into consideration high levels of hydrogen sulfide (H2S) and weight restrictions on the northern outfall sewer (NOS).
“We have moved away from a traditional concrete discharge chamber and instead will be demolishing the existing chamber to install a modular GRP unit,” he said. It has several benefits – it’s lighter, reduces H&S risk, decreases carbon in the manufacturing process, cuts down on installation time on site and provides increased longevity and resilience for the network, he said.
He continued: “These lengths of the mains actually date back to 1977 and they have come under increased pressure from development in the area so, alongside the rehabilitation work, we will also be conducting detailed CCTV surveying of a further 31 metres of the elevated bridge structure that discharges into the NOS to ensure that it is in satisfactory condition.
“We are also very mindful of the proximity of Gallions Reach Shopping Centre, so our plans set out to minimise disruption and to maintain access for businesses and shoppers.”
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